全文获取类型
收费全文 | 85908篇 |
免费 | 4630篇 |
国内免费 | 45篇 |
专业分类
林业 | 3392篇 |
农学 | 2674篇 |
基础科学 | 486篇 |
10897篇 | |
综合类 | 13935篇 |
农作物 | 3117篇 |
水产渔业 | 3899篇 |
畜牧兽医 | 45759篇 |
园艺 | 1031篇 |
植物保护 | 5393篇 |
出版年
2019年 | 792篇 |
2018年 | 1419篇 |
2017年 | 1509篇 |
2016年 | 1329篇 |
2015年 | 1083篇 |
2014年 | 1340篇 |
2013年 | 3736篇 |
2012年 | 2455篇 |
2011年 | 3026篇 |
2010年 | 1997篇 |
2009年 | 1943篇 |
2008年 | 2873篇 |
2007年 | 2809篇 |
2006年 | 2560篇 |
2005年 | 2248篇 |
2004年 | 2152篇 |
2003年 | 2175篇 |
2002年 | 2042篇 |
2001年 | 2489篇 |
2000年 | 2468篇 |
1999年 | 1965篇 |
1998年 | 862篇 |
1997年 | 822篇 |
1995年 | 897篇 |
1994年 | 810篇 |
1992年 | 1571篇 |
1991年 | 1762篇 |
1990年 | 1645篇 |
1989年 | 1650篇 |
1988年 | 1487篇 |
1987年 | 1467篇 |
1986年 | 1553篇 |
1985年 | 1525篇 |
1984年 | 1275篇 |
1983年 | 1184篇 |
1982年 | 775篇 |
1979年 | 1328篇 |
1978年 | 1014篇 |
1977年 | 988篇 |
1976年 | 1069篇 |
1975年 | 1088篇 |
1974年 | 1246篇 |
1973年 | 1199篇 |
1972年 | 1137篇 |
1971年 | 979篇 |
1970年 | 1036篇 |
1969年 | 1056篇 |
1968年 | 972篇 |
1967年 | 991篇 |
1966年 | 885篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
Plasma triglyceride concentration during intravenous infusions of propofol and Intralipid in sheep 总被引:1,自引:0,他引:1
B. M. Q. Weaver D. Raptopoulos † G. E. Staddon W. W. Mapleson‡ 《Veterinary anaesthesia and analgesia》1996,23(1):15-19
Plasma triglyceride concentrations were measured in sheep given Intralipid or propofol, which is carried in a vehicle very similar to 10% Intralipid. A bolus dose was administered followed immediately by an infusion of the same agent for 2 h. In the animals that received propofol, the measured concentration increased by a mean amount of 3.39 mmol/l when the infusion rate was l ml/min (Group Pl) and by 7.13 mmol/l when it was 2 ml/min (Group P2). When 10% Intralipid was administered and infused at 1 ml/min (Group I10), the measured concentration increased only by 0.95 mmol/l. One hour after stopping the infusion, the excess of measured concentration over baseline had decreased in the Pl and I 10 groups to 0.52 and 0.13, respectively, of the corresponding maximum excess. The method adopted for measuring plasma triglycerides is widely used in hospitals; however, an incidental observation revealed that it is inappropriate in the presence of injections of propofol or Intralipid. Despite this, evidence and argument are presented to support the conclusion that, with propofol, plasma triglyceride concentrations increased more rapidly during the infusions and returned to baseline more slowly than with a corresponding amount of Intralipid. 相似文献
82.
D V Wilson 《Veterinary Clinics of North America: Small Animal Practice》1992,22(2):491-494
Any patient presenting for anesthesia and surgery who has a severe debilitating problem is at great risk for a prolonged recovery, renal failure, or hypotension. A stable hemodynamic state should be maintained. Fluid homeostasis should be ensured. Anesthetic induction techniques using narcotics and benzodiazepines are my preferred approach, with maintenance of anesthesia incorporating isoflurane, narcotics, or both or the use of regional anesthesia. 相似文献
83.
Studies on efficacy and stability of a vaccine bait containing ERA strain of rabies virus propagated in a BHK-21 cell line.
下载免费PDF全文
![点击此处可从《Canadian journal of veterinary research》网站下载免费的PDF全文](/ch/ext_images/free.gif)
K F Lawson H Chiu M Matson P Bachmann J B Campbell 《Canadian journal of veterinary research》1992,56(2):135-141
In a dose response study in foxes, the median protective dose of ERA BHK21 vaccine in a blister pack bait was 10(6.0) tissue culture infective doses (TCID)/mL, while artificially aged baits with titers of 10(6.3) TCID/mL induced seroconversion in 78% of foxes. There was no significant difference in the development of antibodies in foxes receiving 1, 2 or 3 mL volumes of vaccine in the bait. When baits were exposed to the elements and fed to foxes over a 21 day period, 85% of the animals seroconverted. Age, sex and the way in which the vaccine container was contacted did not appear to be factors in the responses of these animals. Juvenile foxes, approximately six months of age, were marked more readily with the tetracycline bait marker than older animals. Approximately 25% of foxes did not appear to respond well to vaccination and the titer of the vaccine was a critical factor in producing seroconversion in these animals. 相似文献
84.
125I-labelling was used to characterise the surface components of five stocks of Trypanosoma evansi. Two components of 67 and 60.5 kD were labelled in two of the stocks, a single 60.5 kD component in two other stocks and no components in the remaining stock. These differences are probably related to the labelling method and biochemical differences between the stocks. 相似文献
85.
Dingell v. Baltimore 总被引:1,自引:0,他引:1
B J Culliton 《Science (New York, N.Y.)》1989,244(4903):412-414
86.
The indirect fluorescent antibody test (IFAT) was compared with the enzyme-linked immunosorbent assay (ELISA) for the detection of specific antibodies to Sarcocystis sp. A set of 275 ovine blood samples was examined by both reactions. Cystozoites of Sarcocystis gigantea were used as the corpuscular antigen for the IFAT. For the diagnostics of sarcocystosis by the ELISA technique used the sandwich test of the antibody titration with a soluble antigen which was also prepared from S. gigantea macrocysts. Our studies confirmed that this antigen did not cross-react with Toxoplasma gondii. Titre 40 was determined as the limit one for the IFAT and titre 80 for the ELISA; which was confirmed by the direct detection of cysts in the muscles (Svobodová, 1989). The results of both methods are shown in Table I. 76.7% of the blood samples reacted positively in the IFAT and 83.6% in the ELISA. These methods were found to be suitable and can be utilized for the intravital routine diagnostics. 相似文献
87.
Abstract. The effect of Medicago arborea on erosion on a burnt area was studied in experimental plots near Valencia, Spain, between 1989 and 1992. Its growth and development was studied, and its effect was compared with the natural vegetation (matorral) and bare soil. Medicago decreased soil loss by 41.7% and runoff by 25.7% compared with bare soil. However, under natural vegetation soil loss was 27.5% less than under Medicago. 相似文献
88.
J D Fikes R A Lovell M Metzler W B Buck 《Journal of the American Veterinary Medical Association》1989,194(4):543-544
Two male English Setters were noticed to be breathing rapidly, hyperexcitable, and atactic after roaming a rural area for 2 hours. Both dogs' cost were stained with yellow liquid. One dog died while en route to the veterinarian. Treatment was begun for the surviving dog for what was initially diagnosed to be organophosphorus or carbamate insecticide toxicosis. Before the diagnosis could be confirmed, the second dog died. The yellow liquid on the dogs' skin was identified as dinoseb in high concentrations. Dinoseb is an acutely toxic, substituted dinitrophenolic herbicide believed to act as an uncoupler of electron transport from oxidative phosphorylation. 相似文献
89.
B. W. HERBERT 《Journal of fish diseases》1988,11(4):301-308
Abstract The microsporidian parasite Thelohania sp. was present in a population of Cherax quadriearinatus in the Mitchell River, north Queensland. An infection rate of 7--8% was recorded for the population sampled. Cohabitation, passage of spores through fish, ingestion of spores and injection of blood from an infected individual failed to elicit infection in laboratory held animals. Injection of spores elicited a host responseconsisting of encapsulation and melanization of spores. Further studies are necessary to clarify the taxonomic position and mode of transmission of this parasite. 相似文献
90.
S. Leibovitch B. L. Ma Wanga E. Maloba D. L. Smith 《Journal of Agronomy and Crop Science》1992,169(3):209-215
Aspects of intensive management practices such as high-yielding cultivars, narrow-row spacings and fungicide treatments could potentially increase cereal yields in regions with a short crop-growing season and occasionally dry and hot weather. A field experiment was carried out at McGill University, Canada for three years (1987 to 1989) to test the effects of triadimefon (1-[4-chlorophenoxy]-3,3-dimethyl-1-[1H-1,2,4-triazol-1-yl]-2-butanone, or Bayleton, a trade name) fungicide (0 vs. 140 g a.i. ha−1 ) and row spacing (10 vs. 20 cm) on the yield components, yield and other agronomic traits (spike emergence, days to maturity, leaf disease and plant height) of spring barley ( Hordeum vulgare L.) cv. Cadette, Laurier and Leger. A cultivar by row spacing interaction resulted in a 11 to 13.5 % increase in grain yield due to narrow rows for Laurier in two out of the three years and up to 16 % for Leger in one year. Over the three years grain yields were on average increased 6 to 12 % due to use of the narrower row spacing. Fungicide application to barley at the early heading stage effectively controlled leaf diseases without influence on yield components or grain yield. Our results indicate that some components of intensive management such as narrow row spacing can be applicable in regions with a short crop-growing season. 相似文献